KR101545034B1 - Method and apparatus for diagnosing status of parts in real time in plasma processing equipment - Google Patents

Abstract

An apparatus and method for diagnosing the condition of a consumable part of a plasma reaction chamber is disclosed, the consumable part including at least one conductive element embedded therein. The method includes the steps of coupling a conductive element to a power supply to cause a bias potential for ground to be applied to the conductive element; Exposing the consumable component to plasma erosion until the conductive element pulls current from the plasma upon exposure of the conductive element to the plasma; Measuring current; And evaluating the extent of corrosion of the consumable part due to the plasma based on the measured current.

Description

[0001] METHOD AND APPARATUS FOR DIAGNOSING STATUS OF PARTS IN REAL TIME IN PLASMA PROCESSING EQUIPMENT [0002]

Plasma has been used in many applications such as semiconductor processing processes. Conventional plasma processing equipment produces a plasma with poor thermal and / or chemical properties that wastes a large number of parts exposed to the plasma during processing processes. Because of the aggressive nature of the plasma, repeated contact with the plasma may cause one or more of the components to slowly erode and / or suddenly fail, degrading the performance of the equipment and causing process outcomes to change over time. It is possible.

Therefore, it is important to monitor the status of these parts carefully and replace the parts in a timely manner. If parts are replaced too early, the cost of production is increased by discarding parts that may still be in use. If the parts are left too long before replacement, they may damage other parts of the equipment, resulting in additional costs. For example, if the edge ring in the semiconductor processing chamber is corroded beyond safety limits, the more expensive component, the electrostatic chuck, may be destroyed. Ideally, use the part up to the maximum safety limit, and no more.

The useful lifetime of each component may be estimated through statistical analysis of degradation and failure when deployed in specific environments. However, it is always possible that a part may fail or be replaced earlier than anticipated. Also, in practice, the service life of the part may depend on exactly how the equipment is operated, which may or may not be closely monitored. In addition, it may be necessary to open the equipment to perform the inspection, which interferes with production and results in a certain down-time. Accordingly, it would be desirable to provide the ability to detect events indicative of termination, defects, or failures of the service life of a part during operation of the equipment, and regardless of the application in any particular plasma process. It would be more desirable to provide the ability to monitor the status of each part in real time and the call of an alarm when the end of valid operating life is reached.

Summary of the Invention

According to one embodiment, there is provided a method of diagnosing a condition of a consumable component of a plasma reaction chamber, the consumable component comprising at least one conductive element embedded therein, the method comprising: To cause a bias potential for ground to be applied to the conductive element; Exposing a consumable component to a plasma such that upon exposure of the conductive element to the plasma, the conductive element draws current from the plasma; Measuring current; And evaluating the extent of corrosion of the consumable part due to the plasma based on the measured current.

According to another embodiment, there is provided a consumable component of a plasma reaction chamber, the consumable component comprising a surface formed of a dielectric material and exposed to a plasma, the consumable component comprising: at least one conductive element embedded in the consumable component; A probe circuit coupled to the conductive elements; And a power supply coupled to the probe circuit and ground to apply a bias potential to ground to the conductive elements, the conductive elements being operative to draw current from the plasma upon exposure of the conductive element to the plasma, The probe circuit operates to measure the current.

According to another embodiment, there is provided a consumable component of a plasma reaction chamber, the consumable component comprising a surface formed of a conductive material and exposed to a plasma, the consumable component comprising: a dielectric layer embedded in the consumable component, One or more electrically conductive electrically conductive elements; A probe circuit coupled to the conductive elements; And a power supply coupled to the probe circuit and ground to apply a bias potential to the ground to the conductive elements, the conductive elements being operative to draw current from the plasma upon exposure of the conductive element to the plasma, The circuit operates to measure the current.

Brief Description of Drawings

1 shows a schematic cross-sectional view of a plasma processing chamber with a diagnostic sensor according to one embodiment.

Figure 2 shows an exemplary plot of the signal from the diagnostic sensor of Figure 1 as a function of time.

Figures 3a and 3b show schematic side and cross-sectional views of an edge ring according to another embodiment.

Figures 4A and 4B show schematic cross-sectional views of various embodiments of edge rings.

FIG. 5 shows a schematic cross-sectional view of one exemplary embodiment of a top electrode of the type used in the plasma processing chamber of FIG.

을 따라 취해진, 도 5의 상부 전극의 개략적인 단면도를 도시한다.6 is a cross-

Sectional view of the top electrode of FIG. 5 taken along line II-II of FIG.

Figs. 7A-7C show schematic cross-sectional views of various exemplary embodiments of a top electrode of the type used in the plasma processing chamber of Fig.

details

Referring now to Figure 1, a schematic cross-sectional view of a plasma processing chamber 100 in accordance with one embodiment is shown. It is noted that the chamber 100 is an exemplary device that generates plasma and includes a diagnostic sensor according to one embodiment. Hereinafter, for brevity, the following discussion is limited to sensors for diagnosing components in the chamber 100. However, it should be apparent to those skilled in the art that similar sensor embodiments may be applied to other suitable plasma generation devices.

As shown, the chamber includes a wall 117 for forming a space in which various components for generating a capacitively coupled plasma are disposed. The chamber also includes an upper electrode 102 and an electrostatic chuck 106 for holding the substrate 112 in place during operation. The upper electrode 102 and chuck 106 form a pair of electrodes coupled to an RF power source (not shown in FIG. 1) and are coupled to the top surface of the substrate 112 Thereby generating a plasma. The chamber 100 also includes a ceramic ring 108, a coupling ring 110 disposed between the ceramic ring and the chuck 106, and an edge ring 114 disposed about the edge of the substrate 112 do. The plasma is confined by a confinement ring 104 disposed in a gap between the upper electrode 102 and the chuck 106. [ Some of the gas particles in the plasma pass through the spaces / gaps between the rings 104 and are then evacuated from the chamber by a vacuum pump.

The edge ring 114 includes several functions including positioning the substrate 112 with respect to the chuck 106 and protecting the underlying components that are not protected by the substrate itself from damage by the plasma . In addition, the edge ring 114 uniformly enhances the plasma across the substrate 112. Without the edge ring 114, the substrate 112 will define the outer edge of the chuck electrically and the equipotential lines will bend up sharply near the substrate edge. Thus, without the edge ring 114, the substrate edge will experience a plasma environment that is different from the plasma environment where it is at the center of the substrate, which would result in poor production yield near the edge. A more detailed description of the chamber can be found in co-owned U.S. Patent No. 6,986,765.

Due to the aggressive nature of the plasma, the edge ring 114 may wear over time. As the edge ring 114 wears, plasma characteristics near the damaged areas of the edge ring may change. Changes to the plasma properties may then cause the process results to change over time, and the chamber may reach a point at which the edge ring 114 needs to be replaced.

The diagnostic sensor 115 is coupled to the edge ring 114 to monitor the structural and operating conditions of the edge ring 114 in real time and provide an indication of an event such as the end of the useful life of the edge ring . The sensor 115 includes a probe circuit 118 connected to the probe 116 via a pick-up unit or probe 116 and a conductor wire 119. The probe 116 is embedded within the edge ring 114 such that the probe is completely surrounded by the edge ring 114. In one exemplary embodiment, the probe 116 has the shape of a wire segment or pin. The probe 116 is formed of a conductive material such as metal, but is not limited thereto, and the edge ring 114 is formed of an electrically insulating or dielectric material, but is not limited thereto.

The probe circuit 118 includes a power supply 122 for applying a potential between the probe 116 and ground. The circuit 118 also includes a measuring device 124 and a resistor 120, such as a voltmeter, for measuring the current flowing through the resistor, or the voltage across the resistor. The conductor wire 119 is shown extending from the probe 116 through the chamber wall 117 to the circuit 118. The circuit 118 may be disposed within the chamber and the measurement device 124 may be located outside the chamber wall 117 to provide a signal to the display 124 that is operable to display signals measured by the device 124 to the operator. Unit. ≪ / RTI >

The probe 116 is embedded within the edge ring 114 to a depth corresponding to a diagnostic event such as the end of the useful life of the edge ring 114. [ Probe 116 is biased with a negative dc potential of 10 to 15 volts relative to ground. During operation, a portion of the edge ring 114 covering the probe 116 from the plasma prevents the energetic cations of the plasma from reaching the probe 116. However, upon repeated exposure to the plasma, the cover portion of the edge ring 114 is corroded to expose the probe 116 to the plasma, so that the probe draws the ion current from the plasma. The pulled ion current may flow through the resistor 120 of the probe circuit 118 and be measured by measuring the voltage across the resistor. The plasma can be coupled to ground through the wall 117, the upper electrode 102, or other suitable components, and can complete the path for the ion current drawn by the probe, i.e., Source and forms part of the electrical path for the ion current, and the ground also forms part of the electrical path.

In another embodiment, probe 116 may be biased with a desired amount of dc potential (not shown in Fig. 1) of between 10 and 15 volts relative to ground. In this embodiment, the positive terminal of power supply 122 of Fig. 1 may be connected to resistor 120 and the negative terminal of power supply 122 may be connected to ground. The positively biased probe 116 may draw a negative electron current from the plasma when the edge ring 114 is worn to expose the probe 116 to the plasma. The plasma can be coupled to ground through the wall 117, upper electrode 102, or other suitable components, and completes the path for the electron current drawn by the probe, i.e., the plasma is the source of the electron current Forms part of the electrical path for the electron current, and the ground also forms part of the electrical path.

FIG. 2 illustrates one exemplary plot of the signal from the measurement device 124 of FIG. 1 as a function of plasma exposure time. As the portion of the edge ring 114 covering the probe 116 from the plasma is worn away, the ion current flowing through the resistor 122, or equivalently the voltage across the resistor, as measured by the device 124, It may suddenly increase as shown. This sudden increase in signal strength may be used as an indicator of the point at which the probe 116 is exposed to the plasma. In one embodiment, an operator attention or warning requesting intervention is triggered when the voltage increases to a predetermined threshold voltage V _T corresponding to a diagnostic event such as the end of the valid operating life of the edge ring 114 It is possible. In another embodiment, a warning or notification may be triggered if the voltage indicates a sudden change in value. Thus, by monitoring signals from the measurement device 124, in situ diagnostics of conditions such as the degree of corrosion and the performance of the edge ring 114 can be performed in real time.

As described above, the probe 116 may be biased at a positive dc potential with respect to ground and draw negative electron currents. In such a case, the vertical axis of the plot of FIG. 2 may represent the absolute value of the voltage across resistor 120.

을 따라 취해진, 8개의 프로브들 (302) 을 갖는 에지 링 (300) 의 개략적인 평면 단면도를 도시한다. 간결함을 위해, 도체 와이어 (304) 를 통해 프로브들에 커플링된 프로브 회로는 도 3a에는 도시되지 않는다.In one exemplary embodiment, the sensor 115 may include a plurality of probe pins embedded within the edge ring 114 to provide redundancy or to monitor the integrity of the edge ring in its entirety. Figure 3A shows a schematic side cross-sectional view of an edge ring 300 with a plurality of probes 302 embedded therein. 3B is a cross-

Sectional view of an edge ring 300 having eight probes 302 taken along line 300 of FIG. For the sake of brevity, the probe circuit coupled to the probes via conductor wire 304 is not shown in Fig. 3A.

As shown in FIGS. 3A and 3B, a plurality of probes or probe pins 302 are circumferentially arranged at predetermined angular intervals around the center axis of the edge ring 300. It should be noted that any other suitable number of probes 302 may be embedded within the edge ring 300. In another exemplary embodiment, the probes 302 may be electrically connected to one another via an optional connecting wire 306, wherein the connecting wire 306 is formed of a conductive material and may be embedded within the edge ring 300 It is possible. In this embodiment, all of the probes 302 may be coupled to the probe circuit.

The shape, dimensions, and material compositions of the probe are selected according to the type of application of the probe. In one exemplary embodiment, the diagnostic sensor may comprise a plurality of thin plates coupled to a probe circuit, each plate having a general polygonal or circular plate / disk shape. For example, FIG. 4A shows a schematic cross-sectional view of one exemplary embodiment of an edge ring 400. As shown, a plurality of probes 402 are embedded within the edge ring 400 and arranged circumferentially. Each probe 402 has a flat circular disk shape and is coupled to a probe circuit (not shown in Fig. 4A) via a conductor wire 404. It is noted that the probe 402 may have other suitable shapes, such as a rectangle.

Optionally, a plurality of probes 402 embedded within the edge ring 400 may be connected to each other by a connection wire 406, wherein the connection wire 406 may be formed of a conductive material and may be embedded within the edge ring have. In this embodiment, all of the probes may be coupled to the probe circuit through conductor wires.

FIG. 4B shows a schematic cross-sectional view of another embodiment of the edge ring 410. FIG. As shown, a probe 412 having an annular shape is embedded within the edge ring 410. For simplicity, the probe circuit coupled to the probe 412 via the conductor wire 404 is not shown in FIG. 4B.

The diagnostic sensors of Figs. 1 to 4B can be corroded by the actions of plasma, or can be applied to other suitable components, such as confinement rings, made of electrically insulating or dielectric material. Signals from multiple diagnostic sensors associated with these components can be simultaneously monitored to diagnose conditions of components in real time. For components made of a conductive or semi-conductive material, such as the top electrode 102 (Fig. 1), as discussed with respect to Figs. 5 to 7B, the probe may prevent direct contact between the embedded host component and the probe For this purpose, the probe may be surrounded by a dielectric material. Hereinafter, for purposes of illustration, an upper electrode is described as an exemplary host component formed of a conductive material.

FIG. 5 shows a schematic cross-sectional view of one exemplary embodiment of an upper electrode 500 that may be used in the plasma processing chamber of FIG. FIG. 6 shows a schematic cross-sectional view of the upper electrode 500. For the sake of brevity, the detailed configuration of the electrodes, such as the gas injection mechanism, is not shown in Figures 5 and 6. As shown, the top electrode 500 is associated with a diagnostic sensor 501 that includes one or more probe units 503 embedded within the top electrode. Each probe unit 503 includes a probe 502 comprising a pin or wire segment formed of a conductive material such as metal and an insulating layer 504 surrounding the probe to electrically isolate the probe from the top electrode 500 ). The insulating layer 504 may be formed, for example, by coating a dielectric material on the probe 502. [ The sensor 501 also includes a sensor circuit 506 and one or more conductor wires 508 and each of the conductor wires 508 includes a sensor circuit 506 and a corresponding one of the probes 502 Is coupled to the probe. The conductor wires 508 may be electrically isolated from the upper electrode 500.

In one exemplary embodiment, each probe 502 can be individually coupled to a probe circuit 506 via a conductor wire 508. In another exemplary embodiment, the probes 502 may be electrically connected to each other by an optional connection wire 506, the wire 506 may be embedded within the upper electrode 500, surrounding the wire 506 Is insulated from the top electrode by an insulating layer such as a dielectric coating. In this embodiment, all the probes 502 are coupled to the probe circuit 506. Probe circuit 506 may have components and operating mechanisms similar to circuit 118 of FIG.

(도 5) 에 평행한 방향을 따라 취해진, 상부 전극 (700) 의 일 예시적인 실시형태의 개략적인 단면도를 도시한다. 도시된 바와 같이, 상부 전극 (700) 내에 임베딩된 다수의 프로브 유닛들 (703) 의 각각은, 평탄한 원형 디스크 형상을 갖는 프로브 (704), 및 상부 전극 (700) 으로부터 프로브를 전기적으로 절연시키기 위해 프로브를 둘러싸는 절연 레이어 (702) 를 포함한다. 프로브 (704) 가 직사각형과 같은 다른 적합한 형상들을 가질 수도 있다는 것을 주의한다. 또한, 임의의 적합한 수의 프로브들이 상부 전극에서 사용될 수도 있다는 것을 주의한다.In another exemplary embodiment, each probe may comprise a thin plate formed of, but not limited to, a conductive material and formed in a generally circular or polygonal shape. For example, Fig.

Sectional view of one exemplary embodiment of the top electrode 700 taken along a direction parallel to the top electrode 700 (Fig. 5). As shown, each of the plurality of probe units 703 embedded in the upper electrode 700 includes a probe 704 having a planar circular disk shape and a plurality of probes 704 for electrically isolating the probes from the upper electrode 700 And an insulating layer 702 surrounding the probe. Note that the probe 704 may have other suitable shapes such as a rectangle. It is also noted that any suitable number of probes may be used in the top electrode.

Alternatively, the plurality of probes 704 may be connected to each other by a connection wire 706 similar to the connection wire 506 (FIG. 5). In this embodiment, all of the probes are coupled to the probe circuit through a conductor wire.

In another exemplary embodiment, as shown in FIG. 7B, the probe embedded in the upper electrode may have a general annular shape. Fig. 7B shows a schematic cross-sectional view of the top electrode 710. Fig. As shown, the probe unit 713 embedded in the upper electrode 710 includes an annular probe 714 and an insulating layer 714 that surrounds the probe 714 and electrically isolates the probe 714 from the upper electrode 710. [ (712). The probe 714 may be formed of a conductive material such as a metal and coupled to a probe circuit similar to the circuit 118 of FIG.

7C depicts a schematic planar cross-sectional view of another exemplary embodiment of the top electrode 720. FIG. As shown, the plurality of probe units 723 may be concentrically embedded within the upper electrode 720, and each probe unit 723 may include an annular probe 724, And an insulating layer 722 that electrically isolates the probe 724 from the probe 720. When the upper electrode 720 has a showerhead configuration including a plurality of gas holes, the radial spacing between the probe units may include gas outlets therein. The insulating layer 722 and the probe 724 may be formed of materials similar to the layer 712 and the probe 714, respectively.

The probes shown in Figures 3A-7C can be biased with a desired amount of dc potential of 10-15 volts relative to ground. For example, the positive terminal of the power supply of Figure 5 is connected to a resistor, and the negative terminal of the power supply is connected to ground. For the sake of brevity, the probes positively biased with respect to ground are not described in detail. It should be apparent, however, that the operational and structural features of the sensor embodiments with negatively biased probes are similar to the operational and structural features of the sensor embodiments with positively biased probes.

Although the present invention has been described in detail with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made and equivalents may be resorted to without departing from the scope of the appended claims.

Claims (20)

A method for diagnosing a condition of a consumable part of a plasma reaction chamber,
Wherein the consumable component comprises at least one conductive element embedded therein,
The consumable component status diagnosis method includes:
Coupling the conductive element to a power supply to cause a bias potential for ground to be applied to the conductive element;
Exposing the consumable component to plasma erosion until the conductive element draws current from the plasma upon exposure of the conductive element to the plasma;
Measuring the current; And
And evaluating the degree of corrosion of the consumable component due to the plasma based on the measured current. The method according to claim 1,
Wherein measuring the current comprises:
Interposing a resistor in series between the conductive element and the power supply;
Measuring a voltage across the resistor; And
And determining the current based on the measured voltage. The method according to claim 1,
Further comprising triggering a notification when the current increases to a predetermined threshold level. The method according to claim 1,
Wherein the consumable part is formed of a conductive material and the conductive element is surrounded by an electrically insulating material so that the conductive element is electrically isolated from the consumable part. The method according to claim 1,
Wherein the consumable part is formed of a dielectric material. The method according to claim 1,
Wherein the conductive element has a pin shape. The method according to claim 1,
Wherein the conductive element has a general polygonal shape. The method according to claim 1,
Wherein the conductive element has a generally annular shape. The method according to claim 1,
Wherein the consumable component comprises a plurality of electrically conductive elements electrically connected in series with each other by a conductive wire. The method according to claim 1,
Wherein the current is selected from the group consisting of a positive ion current and a negative electron current. The method according to claim 1,
And replacing the consumable part with a new consumable part. As a consumable part of a plasma reaction chamber,
Wherein the consumable component comprises a surface exposed to a plasma,
The consumable part
Conductive elements embedded within the consumable component and electrically coupled to each other;
A probe circuit coupled to the conductive elements; And
And a power supply coupled to the probe circuit and ground to apply a bias potential to ground to the conductive elements,
Wherein the conductive elements are operative to draw current from the plasma upon exposure of the conductive elements to the plasma, and wherein the probe circuit is operative to measure the current. 13. The method of claim 12,
Wherein the consumable part is made of a dielectric material and is selected from the group consisting of an edge ring and a confinement ring. 13. The method of claim 12,
Wherein the power supply is a DC power source. 13. The method of claim 12,
Wherein the probe circuit comprises a resistor and a voltmeter for measuring the potential across the resistor. 13. The method of claim 12,
Each of the conductive elements having a shape selected from the group consisting of pins, polygons, circles, and annular. 13. The method of claim 12,
Wherein the conductive elements are electrically connected to each other by a conductive wire. 13. The method of claim 12,
The consumable part is formed of a conductive material,
Wherein the conductive elements are embedded in the consumable component and are electrically isolated from the consumable component by a dielectric layer. 19. The method of claim 18,
Wherein the consumable component is an electrode for generating a plasma. 13. A method of processing a semiconductor substrate in a plasma reaction chamber comprising the consumable component of claim 12.

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